FireLion3
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What's the best way to recover Pd from Pd-Organic complexes?
I have a bunch of Pd that is bound to some organic (phosphine) complexes (in the form of PdCl2), and I want to recover the Pd for reuse.
I'm not sure if Aqua Regia will dissolve it. I thought maybe I could pyrolyze it first, but that may form Pd Oxides and I'm not sure if those will
dissolve in aqua regia either.
Would it be as simple as heating the complex to a high enough temperature (300c+) to decompose/vaporize the organics, and siphon them off down the
drain? I am not sure whether this will leave behind the Pd in salt form, or in metal/oxide form... I suspect if the temperature is kept low enough,
the salt will remain in tact?
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Metacelsus
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Why not just recover the Pd(PPh3)2Cl2 as the complex? It's pretty useful itself. (I use it in my University research
lab for Sonogashira couplings.)
Heating in an inert atmosphere would likely leave you with just palladium chloride. If you wanted palladium metal, you could electrolyze that.
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FireLion3
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I'll try heating it, though I don't think I have an inert atmosphere at my disposal, but metal salts don't usually oxidize at such low temperatures
(under 350c), do they?
It's not just a palladium complex, but a mix of different complexes and polymeric material from faulty experiments - in other words, it's my Pd-waste
container.
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Metacelsus
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Heating in air is probably fine, but you could also try heating under vacuum (and this might lower the decomposition temperature). If it's a waste
container, you're likely to get some carbonized gunk as well. Make sure to do this in a vessel you don't care about.
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Dr.Bob
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This is a good question, I have collected much Pd crud over the years, and have lots of old bits of bad catalysts, I have been curious how practical
it would be to combine and reuse. I have even wondered about just burning it all, then dissolving somehow and putting on carbon to reduce via
hydrogenation for Pd/C catalyst. Just not sure how to do that.
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DJF90
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Quote: Originally posted by Dr.Bob  | | This is a good question, I have collected much Pd crud over the years, and have lots of old bits of bad catalysts, I have been curious how practical
it would be to combine and reuse. I have even wondered about just burning it all, then dissolving somehow and putting on carbon to reduce via
hydrogenation for Pd/C catalyst. Just not sure how to do that. |
Please find attached some scanned pages to assist you in your endeavours. If you're aiming for Pd/C as a final product, then proceed via palladium
chloride and follow existing methods for reduction on inert support material (see http://www.orgsyn.org/demo.aspx?prep=CV3P0685).
Attachment: Palladium recovery 03-Mar-2016 00-04-31.pdf (1MB)
This file has been downloaded 308 times
[Edited on 3-3-2016 by DJF90]
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Dr.Bob
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Thanks, that is a great paper, I have never seen it mentioned before. I wish I had saved all of the Pd waste from a few years back when I used a lot
of it. It went to a waste company, where they may have recovered it, but not sure. Likely not worth it for small amounts.
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